Pid Controller - Zener MSC-3 Instruction Manual

MSC-3 Extended Features Option Manual
ZENER

PID CONTROLLER

The PID controller of the MSC-3 include the following features:
• Adjustable Integrator anti-windup
• Adjustable Output saturation with anti-windup
• Open loop to closed loop initialization
• Selectable set point and feed forward input signals
• Input / Output signal spanning
• Process variable UNDER and OVER Alarm
PID Structure
PID controllers (also referred to as Three-Term controllers) are used to stabilize and/or regulate a process
at a desired operating point. PID controllers function by finding the difference between the required
operating point (the Setpoint Variable or SV) and a measured process quantity (the Process Variable or
PV). This difference between the two signals is called the 'error'. In regulator mode, the PID controller
operates to reduce the error to zero at which point the measured quantity is equal to the required
operating point.
P33 SVchoice
error
Σ
-
ANALOG INPUT
SCALING
TRANSDUCER
22
ANTI WINDUP
CALCULATION
P29 + I Clamp%
I (error)
P27 Ti (Sec/r)
P30 - I Clamp%
P28 Td (sec) x D (error)
P39 PV Over
(Threshold)
OVER
UNDER
P40 PV Under
(Threshold)
PROCESS
PID FUNCTION BLOCK DIAGRAM
IM00087B
P34 FF Choice
+
100
+
Σ Σ
+
P26 PB (%)
+
+
Σ
+
P39 PV Over (digital output)
P40 PV Under (digital output)
RAMP
3Ø
AND
M
INVERTER
WATCH
DOG
P31 + 0 Clamp%
P32 - 0 Clamp%
P38 PID output